Rack-and-snail strike clock



1.s14,1ss

Jan. 11, 1927.

F. x. WEHRLE RACK AND SNAIL'STRIKE CLOCK Fild may 25. 1926 11" H "nun Patented Jan. 11, 1927.

UNITED STATES PATENT QFFICE.

FRANK X. WEHRLE, OF THOMASTON, CONNECTICUT, ASSIGNOR TO SETH THOMAS CLOCK 00., 0F THOMASTON, CONNECTICUT, A CCRPORATION.

RACK-AND-SNAIL STRIKE CLOCK.

Application filed May 25,

Fig. 1 is a view in front elevation of a rack-and-snail strike-clock embodying my invention Fig. 2 is a detached view in inside elevation of my improved rack stop-arm unit;

Fig. 3 is a view thereof in front elevation with its spring-arm swung out of line with its stop-arm;

Fig. 1 is a view of the unit in longitudinal section on the line lt- 1 of Fig. 2;

Fig. 5 is a view of the unit in transverse section on the line 55 of Fig. 2;

Fig. 6 is a detached view in elevation of the rockable-pin; and

Fig. 7 is a detached View in front elevation of the stop-arm.

My invention relates to an improvement in strike-clocks of the rack-andsnail type, the object being to provide the stop-arm unit of such a. mechanism with a stop-pin relatively unyielding in the discharge of its stop-function, but readily yielding to permit the turning of the snail in either direction in setting the strike side of the movement without deforming or deranging either the pin or the snail.

lVith these ends in view, my invention consists in a stop-arm unit for a racloandsnail strike-mechanism, the said unit having a stop-arm, and a stop-pin mounted in the said stop-arm so as to be substantially rigid therewith in the plane of its stopfunction and rockable in a plane substan tially at a right angle thereto.

My invention further consists in a stoparm unit for a rack-and-snail strike-111echanism, such unit having certain details of construction and combinations of parts as will be hereinafter described and pointed out in the claims.

In carrying out my invention, as herein shown, I employ a rack stop-arm unit comprising a stop-pin 10 having a substantially hemispherical base 11 from which it centrally projects and with which it is preferably made integral. The said base 11 seats in a substantially hemispherical socket 12 formed by cupping the outer end of the rack stop-arm 13, and is yieldingly held in such socket by the engagement of its flat face or bottom by a spring-arm 14 which, with the said stop-arm 18, is mounted upon a hub 15, carrying the rack-arm 16 with. its toothed rack 17, and oscillating on a stud 18 projecting from the front face of the front The side-walls of the slot 20 prevent the lateral rocking of the pin 10, whereby it is maintained substantially rigid in the discharge of its stop-function, in which it coacts in the usual manner with the steps of the snail 21, which, with the arm 16 and rack 17 aforesaid, may be of any standard construct-ion. On the other hand, the slot 20 permits the rocking of the pin under the control of the spring-arm 14, which eX- erts a constant effort to return the pin into its normal position, in which it stands at a. right angle to the plane of the two arms, the pressure on the pin when discharging its normal function of stopping the falling of the rack being exerted. at a right angle to the pressure exerted upon it by the snail when the same is turned either forward or back in setting the strike side of the clockmovement. Thus, when the snail is turned to the right or to the left, as the case may be, in setting the hands of the clock, the pin is rocked to the right or to the left, as shown by broken lines in Fig. 1, so as to permit the rotation of the snail in either direction Without distorting or damaging either the pin or the snail.

I claim:

1. A stop-arm unit for rack-and-snail strike-e10cit-movements, the said unit having a stop-arm, and a stop-pin mounted in the said stoparm so as to be substantially rigid th rewith in the plane of its stop-function and rockable in a plane substantially at a rigat angle thereto.

2. A stop-arm unit for rack-and-snail st ke clock-movenicnts, comprising a stop arm having a hemispherical socket intersected by a. slot, pin having a substantially hemispherical base located in the said socket and slot, and a spring for engaging with the said base to yieldingly hold it in the socket of the said arm.

A stop-arm unit for rack-and-snail strike clock-movements the said unit comprising a stop-arm formed with ahemispherical socket bisected by a slot, a pin pro- Vided with a substantially hemispherical base seated in the said socket and passing through the said slot in which it is held against lateral movement by the side-walls of the slot and permitted to oscillate parallel with the slot, and a spring-arm complementingthe stop-arm aforesaid and engaging with the base of the pin.

4-. A rack-and-snail strike-mechanism having a rack-arm provided with a rack, a snail, a stop-arm having; a substantially hemispherical socket bisected by a slot, a hub connecting the said arms, a spring-arm also carried by the said hub and having bearing upon one face of the said stop-arm, one of the said arms being swivelled with respect to the other, and a pin having a hemispherical base located in the socket and slot of the stop-arm and held in place therein by the engagement of the said spring-arm with the said base.

5. A. stop-arm unit for rack-andsnail strike-clocks, comprising a hub, a rack stoparm mounted thereupon and formed with a cup-shaped socket bisected by a slot, a spring-arm carried by the hub, bearing upon one face of the stop-arm and extending over FRANK X. 'WEHRLE. 

